Your basal metabolic rate (BMR) is estimated with the Mifflin-St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or − 161 for women. Multiplying BMR by an activity factor (1.2 to 1.9) gives your total daily energy expenditure (TDEE), the calories you burn in a typical day. Eating about 500 kcal below TDEE leads to roughly 1 lb (0.5 kg) of loss a week; 250 above gives slow gain. The results never go below 1,200 kcal here, a common minimum for unsupervised diets.
Example: a 30-year-old man at 170 lb and 68 in has a BMR of about 1,706 kcal. With moderate activity (× 1.55) his TDEE is about 2,644 kcal a day.
It is an estimate, usually within 10%. Track your weight for 2 to 3 weeks and adjust the calories up or down based on what actually happens.
BMR is what your body burns at complete rest. TDEE adds movement, exercise and digestion, so it is always higher.
If unsure, choose the lower one. People tend to overestimate how much they move.
See also: BMR calculator · BMI calculator · body fat calculator
Turn your calories into grams with the macro calculator.
How much should you drink? Try the water intake calculator.
Ready to set a goal? Try the weight loss time calculator.